20M chip not remembering download

[michael boyd]

Hi

the program downloads to the chip and works fine. However when I disconnect the serial plug it doesn't work at all. Any ideas?

regards
michael

 

[BeanieBots]

10k pull-down resistor missing from download circuit?

 

[Dippy]

Please post your circuit. How does your circuit (the download and reset part) compare with those in Manual 1 ?

 

[michael boyd]

a bit more info

I am using a 20M chip .8 outputs connected to relays. The 8 inputs are held low. the program is switching on and off the relays one at a time. the program was created in LOGICATOR. It works fine until I unplug the serial stereo plug. Then nothing works. When I plug it in it still doesnt work until I reprogram the chip, then works fine.

Could I have damaged the chip

regards
michael

 

[MartinM57]

Always good to have more info, but the crucial area would seem to be the circuitry around the download interface and the stereo plug socket. Circuit diagrams and pictures will help us help you..

 

[hippy]

It seems unlikely you have damaged the chip as it still works when connected and after each download.

Can you post a circuit diagram as previously requested ?
A copy of your flowchart will also help.

Have you tried a simpler flowchart, just flashing a single LED say, and seeing how that responds when disconnected ?

 

[Dippy]

Even a simple pen/scanned image of your circuit will help please.
We don't need a full CAD image.

 

[michael boyd]

hi

thanks for the quick reply

currently i am working on a boat in sydney (its 10:40pm) and struggling to write email. I never drew a circuit diagram but used the pulldown resistors from the manual and for the relays. Its all mounted on a kiwi patch board, relays on seperate board. the program (sorry, not on this laptop) is pin0 high wait .5 low wait .5, pin1 high wait .5 etc: all the way to pin7 so Ican see all the relays work, one at a time.

I think it worked with other smaller programs. Maybe it is too big. Will try smaller program when I get a chance as was suggested. Could it be this simple?

regards
michael

 

[michael boyd]

here is a picture of the kiwi patch board and relays. below it is a sd21 servo driver that is my next drama, anyway one step at a time. as you can see by the layout , I am new to this

regards
michael

 

[hippy]

It seems odd it would work with download cable connected but not without if it were an electrical interference problem but that could be the case and it would be worth trying without relays and other hardware connected to the circuit, using LED's to determine what the outputs are doing.

If the board was tested with cable in one place and is being used in a different place without the cable that could be an explanation.

You need to go back to as simple as possible, hence a simple LED flash program. If that works, and works with the download cable disconnected, you can then move forward a step at a time, see what makes it stop working.

 

[slimplynth]

I like the look and sound of this project... in your picture... the tag that says 'kettle' and you talk of servos too? Please tell me its wallace and gromit alarm styled clock

 

[michael boyd]

thanks for all the replies

when I got home from work I couldnt resist having a fiddle with it and supprise supprise, when I connected power to it, with the serial connection still disconnected, it worked.

All I can think of is that one of my connections must be a bit suss.

I ran the circuit about 50 times in amasement that it actually worked watching the led light show as the relays turned on and off in sequence.

and it is a tea maker (well one day hopefully it will work)

My next problem is the sd21 controller. I think the correct thing is to start a new string

 

[Dippy]

.... and check all your connections before posting a query
PS. Glad it's all working a lesson learnt.

 

[michael boyd]

the download circuit is the one in the manual, with the 10 and 22k resistor.
What I have noticed is that every time I download a new program, it works and then when I pull out the stereo plug it stops working. Then I turn the power off and back on ( after about 20 seconds) and the new program works fine.

Is this sometimes normal?

regards
michael

 

[Dippy]

When done correctly you won't have errors like this.

Most of the time the cure is thorough checking of connections, wiring and schematic. Most threads with similar issues usually end up with: "ah, I had my wires crossed" or "I forgot the pullup or pulldown res" or "That breadboard that Stan sold me has bits cut off and won't work".

The bottom line (genuine component faults aside) is to check again and again. Sometimes connectors going into breadboard can be awful, some people's soldering is terrible, sometimes the schematic is misinterpreted/misread. And sometimes it requires a second pair of eyes to spot a mistake.

Maybe your connector is conencted incorrectly or duff.

 

[BeanieBots]

the download circuit is the one in the manual, with the 10 and 22k resistor.
What I have noticed is that every time I download a new program, it works and then when I pull out the stereo plug it stops working. Then I turn the power off and back on ( after about 20 seconds) and the new program works fine.

Is this sometimes normal?

regards
michael

NO, this is not normal.
Two main potential causes.
First is what I mentioned in post#2. Have you checked that it is actually there and connected correctly and correct value?

The second possibility is a 0v line missing. The download cable supplying a 0v but obviously only when plugged in.

 

[hippy]

As you're having problems with this 20M and with the 18X of the multi-channel servo board - though that now seems to download okay on breadboard - I'm wondering if it's not some problem related to power supply, environment you are working in or something else odd or unusual.